Starter fertilizer is defined as the small quantity of fertilizer nutrients applied in close proximity to the seed at planting by growers of crops. In some instances, the practice entails placing the fertilizer into the seed row directly with the seed and this is often referred to as a “pop up” fertilizer. Growers of crops use starter fertilizers to enhance the development of emerging seedlings by supplying essential nutrients in accessible locations near the roots. This is especially important when crops are planted into cold, wet soils and/or when seeding into minimum tillage situations.
Phosphorus is routinely used in starter fertilizers/pop up applications. However, phosphorus is immobile in the soil and subsequently small seedling roots have difficulty obtaining the necessary amounts for rapid growth. For these reasons, phosphorus is routinely used as a starter/pop up fertilizer, even when overall phosphorus levels in a field may be adequate or high. For example, recommendations call for 35 kg P2O5 per hectare. However, phosphate in the soil can interact with other nutrients and immobilize them.
Furthermore, there are obvious environmental concerns regarding high soil phosphate levels leaching into the environment as well as potential toxicity to seeds and plants. As one skilled in the art knows, P2O5 is an industry term, used to refer to a source of phosphate.
In certain situations, zinc also may be used by growers as a component of a starter fertilizer. Like phosphorus, zinc is highly immobile in soil. In situations where soil tests indicate that zinc levels are inadequate or marginal, growers will often use zinc as a component of a starter as well.
Magnesium is not commonly considered as a starter fertilizer and consequently is typically not used as a component of a starter fertilizer. Rather, it is usually added as a secondary nutrient or alternatively as a portion of a liming program (Dolomitic lime).
Work in western Iran and published in the Journal of Soil and Sediment (Khanlari, Z. V. and Jalali, M, 2011; “The effect of sodium and magnesium on kinetics of phosphorus release in some calcareous soils of western Iran”, Soil and sediment: An International Journal 20:4, 411-431) looked at the impact of magnesium and calcium ions in irrigation water on the availability of phosphorus in soils in Iran. The researchers noted that irrigation water that had a high calcium level relative to magnesium was detrimental to levels of available soil-P relative to the reverse situation (high Mg and low Ca) which was “friendly” to soil status with respect to high available P. However, this paper focuses solely on irrigation water and does not teach or suggest the potential for inventing a product that manipulated magnesium levels as a component of a synergistic approach to phosphorus fertilizer dynamics.
Work at Brigham Young University in 2011 attempted to characterize the interaction between zinc and phosphorus fertilizer (but not magnesium) and this work found that “when varying both P and Zn, increasing Zn levels stimulated P uptake when ample P was present in the soil—but this did not occur when P was deficient. (Brandt, A, B Hopkins, V Jolley, B Webb, B greenwood and J Buck, 2012:” Phosphorus and zinc interactions and their relationships with other nutrients in maize grown in chelator buffered nutrient solution, J Plant Nutrition 35:1, 123-141).
Thus, it has been demonstrated that water with low magnesium and high calcium was detrimental to uptake of soil-available phosphate while low calcium, high magnesium water was not detrimental.
Furthermore, it was established that zinc stimulated phosphate uptake when phosphate was present in excess but not when phosphate was deficient.